The present invention generally relates to the field of voltage regulators, and especially relates to an uninterruptible power supply.
Please refer to FIG. 1(a) which is a schematic diagram illustrating an isolated type of a mechanical regulator according to the prior art. As shown in FIG. 1(a), the isolated type of a mechanical voltage regulator 100 includes an isolated transformer 101, a relay 102, and an input voltage sensor 103. The input voltage sensor 103 is used to sense the input voltage Vin, and then a trigger signal is generated thereby in order to actuate the relay 102. Accordingly, the turn ratio of the isolated transformer 101 can be adjusted by turning on and off the relay 102. By the adjustment of the turn ratio, the output voltage Vout can be stabilized at a predetermined level.
Please refer to FIG. 1(b) is a schematic diagram illustrating a non-isolated type of a mechanical voltage regulator according to the prior art. As shown in FIG. 1(b), the non-isolated type of a mechanical regulator 200 includes a non-isolated transformer 201, a relay 202, and an input voltage sensor 203. The input voltage sensor 203 is used to sense the input voltage Vin, and then a trigger signal is generated thereby in order to actuate the relay 202. Accordingly, the turn ratio of the isolated transformer 201 can be adjusted by turning on and off the relay 202. By the adjustment of the turn ratio, the output voltage Vout can be stabilized at a predetermined level.
According to the aforementioned art, the employment of the tap-changing transformers 100, 200 was often adopted in stabilizing the system voltage at a customer side. By tuning the transformer taps to reach the expected turn ratio, the input voltage can be boosted or reduced to meet the application need while the load voltage is maintained at a certain level. This strategy seems feasible, yet their speed response and voltage regulation are restricted to the use of mechanical tap changers. Moreover, the bulk volume of the transformer may deteriorate the system encasement, thereby affecting the cost of the system.
Please refer to FIG. 2(a). FIG. 2(a) is a schematic diagram illustrating an electronic voltage regulator according to the prior art. As shown in FIG. 2(a), the electronic voltage regulator 300 consists of at least one electronic switch 301, at least one resistor 302, at least one capacitor 303, and at least one inductor 304. Also a high frequency electrical switching technique is employed in the electronic voltage regulator 300 to stabilize the output voltage Vout.
Please refer to FIG. 2(b). FIG. 2(b) is a schematic diagram illustrating an electronic voltage regulator according to the prior art. As shown in FIG. 2(b), the electronic voltage regulator 400 consists of at least one electronic switch 401, at least one resistors 402, at least one capacitors 403, and at least one inductor 404. Also a high frequency electrical switching technique is employed in the electronic voltage regulator 300 to stabilize the output voltage Vout.
The conventional electronic voltage regulators employ the power transistors and inductors to regulate input energy and increase the circuit ability to stabilize the output voltage. However, in these cases there exist large voltage phase differences between the system input and output. An additional safety design for an I/O bypass circuit becomes difficult and may degrade the operational reliability of the system. Besides, it is also hard to expand the voltage regulators with the function of Uninterruptible Power Supplier (UPS) due to less possibility of embedding DC batteries in these systems. It is therefore attempted by the applicant to deal with the above situation encountered with the prior art.
It is therefore an object of the present invention to propose an electronic voltage regulator and a control method thereof. Especially, when the electronic voltage regulator further includes an energy storage device, the inventive voltage regulator can be used as an uninterruptible power supply.
According to an aspect of the present invention, the electronic voltage regulator includes input terminals electrically connected to an power source which provides an input voltage, output terminals for providing a stable output voltage, a power converter electrically connected to the power source for generating a DC voltage and then converting the DC voltage to generate a compensation voltage to compensate the output voltage when the output voltage is different from a predetermined value, a switch with a first terminal electrically connected to the power source, a transformer with a primary winding and a secondary winding, wherein a first terminal of the primary winding electrically connected to an output terminal of the power converter, a second terminal of the primary winding electrically connected to a second terminal of the output terminals, a first terminal of the secondary winding electrically connected to a first terminal of the output terminals, a second terminal of the secondary winding electrically connected to a second terminal of the switch, and a third terminal of the switch electrically connected to the first terminal of the primary winding, and a switching control device electrically connected to the power converter for controlling the power converter to stabilize the output voltage.
Preferably, the power source is an AC power.
Preferably, the electronic voltage regulator further includes a DC-DC converter electrically connected to the DC voltage for providing a transformation of the DC voltage.
Preferably, the electronic voltage regulator further comprises a energy storage device electrically connected to the DC-DC converter in which the electric energy of the DC voltage charges the energy storage device through the DC-DC converter when the input voltage is within a specific range, and the electric energy of the energy storage device is transformed to compensate the DC voltage when the input voltage is out of the specific range.
Preferably, the energy storage device is a battery.
Preferably, the electronic voltage regulator is an uninterruptible power supply (UPS).
Preferably, the DC voltage is a DC-Bus voltage.
Preferably, the transformer is a variable voltage source depending on a connection configuration of the switch.
Preferably, the switching control device controls the compensation voltage having a phase difference with the input voltage and thereby keep the compensating power to be a positive value.
Preferably, the connection configuration of the switch includes a first connection configuration in which the second terminal of the switch is electrically connected to the first terminal of the switch to form a conducting path when the input voltage is within a specific range, and a second connection configuration in which, the second terminal of the switch is electrically connected to the third terminal of the switch to form a conducting path when the input voltage is out of the specific range.
Preferably, the power converter further includes an output switch assembly electrically connected to the DC voltage for converting the DC voltage to provide the compensation voltage to stabilize the output voltage.
Preferably, the switching control device obtains one group of voltages and one group of phases by feedback of the input voltage, the output voltage, and the DC voltage and thereby a pulse width modulation (PWM) signal is generated through the output switch assembly to stabilize the output voltage.
Preferably, the switching control device includes a DC voltage sensor unit electrically connected to the DC voltage for sensing the DC voltage to generate a first signal according to a magnitude of the DC voltage, a first voltage compensator unit electrically connected to the DC voltage sensor for transforming the first signal to a second signal, an input voltage sensor unit electrically connected to the power source for sensing the input voltage to generate a third signal, a phase lock loop unit electrically connected to the input voltage sensor unit for sensing a phase of the third signal to generate a first phase signal, a phase shift unit electrically connected to the phase lock loop unit for processing 90xc2x0 phase shift of the first phase signal to generate a second phase signal, a multiplier unit electrically connected to the an output terminal of the first voltage compensator unit and the phase shift unit for multiplying the second signal by the second phase signal to generate a fourth signal, an output voltage sensor unit electrically connected to the output voltage for sensing the output voltage to generate a fifth signal having a magnitude and a phase, a AC-to-DC converter unit electrically connected to the output voltage sensor unit for transforming the fifth signal to a sixth signal, a second DC voltage compensator unit electrically connected to the AC-to-DC converter unit for transforming the sixth signal to generate a seventh signal, a second multiplier unit electrically connected to the second DC voltage compensator unit for multiplying the seventh signal by the first phase signal to generate an eighth signal, an adder unit electrically connected to an output terminal of the first multiplier unit and an output terminal of the second multiplier unit for adding the fourth signal and the eighth signal to generate a command tracking signal, an AC command tracking control unit electrically connected to an output terminal of the adder unit and an output terminal of the output voltage sensor unit to compare the command tracking signal with the fifth signal to generate a trigger signal, and a PWM generator electrically connected to the AC command tracking control unit for transforming the trigger signal to a PWM signal, thereby driving the output switch assembly to provide the compensation voltage to stabilize the output voltage.
Preferably, the first signal, the second signal, the third signal, the sixth signal, and the seventh signal are DC signals.
Preferably, the fourth signal, the fifth signal, the eighth signal, and the command tracking signal are AC signals.
According another aspect of the invention, the control method applying an electronic voltage regulator which comprises input terminals electrically connected to an power source which provides an input voltage, output terminals for providing a stable output voltage, a power converter electrically connected to the power source for generating a DC voltage and providing a transformation of the DC voltage to generate a compensation voltage, a switch, a transformer electrically connected between the power converter, the switch, and output terminals, wherein the transformer is a variable voltage source to stabilize the output voltage depending on a connection configuration of the switch, including the steps of judging whether the output voltage is within a specific range, determining a connection configuration of the switch, generating the compensation voltage through the power converter and the transformer, controlling the compensation voltage having a phase difference with the input voltage and keeping the compensating power to be a positive value, and thereby utilizing the compensation voltage to stabilize the output voltage.
Preferably, the electronic voltage regulator further comprises a DC-DC converter electrically connected to the DC voltage for providing a transformation of the DC voltage.
Preferably, the electronic voltage regulator further comprises a energy storage device electrically connected to the DC-DC converter in which the electric energy of the DC voltage charges the energy storage device through the DC-DC converter when the input voltage is within a specific range, and the electric energy of the energy storage device is transformed to compensate the DC voltage when the input voltage is out of the specific range.
Preferably, the energy storage device is a battery.
Preferably, the electronic voltage regulator is an uninterruptible power supply (UPS).
Preferably, the connection configuration of the switch includes a first connection configuration in which the second terminal of the switch is electrically connected to the first terminal of the switch to form a conducting path when the output voltage is within a specific range, and a second connection configuration in which the second terminal of the switch is electrically connected to the third terminal of the switch to form a conducting path when the output voltage is out of the specific range.
According a further aspect of the invention, the electronic voltage regulator includes input terminals electrically connected to an power source which provides an input voltage, output terminals for providing a stable output voltage, a power converter electrically connected to the power source for generating a DC voltage and then converting the DC voltage to generate a compensation voltage to compensate the input voltage when the input voltage is different from a predetermined value, a switch with a first terminal electrically connected to the power source, a transformer with a primary winding and a secondary winding, wherein a first terminal of the primary winding electrically connected to an output terminal of the power converter, a second terminal of the primary winding electrically connected to a second terminal of the output terminals, a first terminal of the secondary winding electrically connected to a first terminal of the output terminals, a second terminal of the secondary winding electrically connected to a second terminal of the switch, and a third terminal of the switch electrically connected to the first terminal of the primary winding, and a switching control device electrically connected to the power converter for controlling the power converter to stabilize the output voltage.
Preferably, the electronic voltage regulator ether comprises a DC-DC converter electrically connected to the DC voltage for providing a transformation of the DC voltage.
Preferably, the electronic voltage regulator further includes a energy storage device electrically connected to the DC-DC converter in which the electric energy of the DC voltage charges the energy storage device through the DC-DC converter when the input voltage is within a specific range, and the electric energy of the energy storage device is transformed to compensate the DC voltage when the input voltage is out of the specific range.
Preferably, the energy storage device is a battery.
Preferably, the electronic voltage regulator is an uninterruptible power supply (UPS).
Preferably, the transformer is a variable voltage source depending on a connection configuration of the switch.
Preferably, the switching control device controls the compensation voltage having a phase difference with the input voltage and thereby keeps the compensating power to be a positive value.
Preferably, the connection configuration of the switch includes a first connection configuration in which the second terminal of the switch is electrically connected to the first terminal of the switch to form a conducting path when the input voltage is within the specific range, and a second connection configuration in which the second terminal of the switch is electrically connected to the third terminal of the switch to form a conducting path when the input voltage is out of the specific range.
Preferably, the power converter further comprises an output switch assembly electrically connected to the DC voltage for converting the DC voltage to provide the compensation voltage to stabilize the output voltage.
Preferably, the switching control device obtains one group of voltages and one group of phases by feedback of the input voltage, the output voltage, and the DC voltage and thereby a pulse width modulation (PWM) signal is generated through the output switch assembly to stabilize the output voltage.
The present invention may best be understood through the following description with reference to the accompanying drawings, in which: